When the Earth passes through the dust trail left by a comet, meteors multiply for a few nights. The Perseids peak around 12 August and the Geminids around 14 December, with up to 100 to 150 meteors an hour in ideal conditions. Watch them with the naked eye, lying down, away from lights.
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Related terms
- Meteor
The streak of light from a speck of space dust, often smaller than a grain of sand, burning up as it enters the atmosphere around 80 to 100 km high, at 11 to 72 km/s. A very bright meteor is called a fireball. A piece that sometimes reaches the ground is a meteorite.
- Radiant
The point in the sky from which the meteors of a shower seem to stream, a perspective effect like railway lines meeting in the distance. It gives the shower its name: the Perseid radiant is in Perseus. The higher it is, the more meteors you see; no need to stare at it, though.
- ZHR (zenithal hourly rate)
The number of meteors one observer would see in an hour under a perfect sky (limiting magnitude 6.5), with the radiant at the zenith. It is a theoretical maximum: in practice you often see two or three times fewer. For the Perseids it is about 100.
- Comet
A block of ice and dust a few kilometres across which, as it nears the Sun, grows a coma and tails. The curved, yellowish dust tail and the straight, bluish gas tail point away from the Sun. Their brightness is hard to predict.
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